Cubemap generation - some questions

[Rastar]

After some time off I am picking up my PBR stuff for Leadwerks again. For the indirect specular lighitng I need special cubemaps that I would like to generate using the Leadwerks API. I would prefer to stay in Lua.

 

I am doing it currently like this

local cameraBuffer = Buffer:Create(self.resolution, self.resolution, 1, 0)
local cubemap = Texture:CubeMap(self.resolution, self.resolution, Texture.RGB)

cameraBuffer:Enable()
for i = 1,6 do
camera:SetRotation(self.cameraRotations[i])
cameraBuffer:SetColorTexture(cubemap, 0, i-1)
App.world:Render()
end
cameraBuffer:Disable()
Context:SetCurrent(App.context)

 

Now

• Running this code gives me a "Asset map vaue is different" error, though the game continues normally. I don't know what this means?
  
• What is the second parameter to Buffer:SetColorTexture()? The mipmap level?
  
• I'm assuming that a cubemap is created by specifying the width and height of a single face (rather than width*6), is this correct?
  
• As I see it, there currently is no way to save a texture to disk (or is there?). Would it be possible to add this to the (Lua) API?
  

[Rastar]

Bump. Anybody?

 

I've put a screenshot of my WIP in the gallery

 

http://www.leadwerks.com/werkspace/page/viewitem?fileid=462724265

 

but without indirect specular lighting from (special) cubemaps this won't be the real deal ;-)

[shadmar]

I would probably do it something like this (but it always renders black)

 

function Script:Start()

   --get workd,context etc..
   self.context=Context:GetCurrent()
   self.world=World:GetCurrent()
   self.resolution=1024

   --fetch a camara
   if self.camera==nil then
       for i=0,self.world:CountEntities()-1 do  --CountEntities is not a supported command
		    if self.world:GetEntity(i):GetClass()==Object.CameraClass then
			  self.camera=self.world:GetEntity(i)  --GetEntity is not a supported command
			  tolua.cast(self.camera,"Camera")
			  System:Print(self.world:GetEntity(i):GetClassName())
			  break
			 end
       end
   end

   --cube directions
   self.cameraRotations = {
       Vec3(0,0,0),
       Vec3(0,180,0),
       Vec3(-90,-90,0),
       Vec3(90,-90,0),
       Vec3(0,-90,0),
       Vec3(0,90,0)
   }

   --make cam buffer
   self.cameraBuffer = Buffer:Create(self.resolution, self.resolution, 1, 0)
   self.cameraBuffer:GetColorTexture():SetFilter(Texture.Pixel)

   --make cube buffer using cubemap texture
   self.cubebuffer =  Buffer:Create(self.resolution, self.resolution, 1, 0)
   self.cubemap = Texture:CubeMap(self.resolution, self.resolution)
   self.cubebuffer:SetColorTexture(self.cubemap)



   --ok warap the cubemap around something
   model=Model:Box(10,100,10)
   material=Material:Create()
   shader=Shader:Load("Shaders/Editor/SkyBox2.shader")


   material:SetShader(shader)
   model:SetMaterial(material)
end



function Script:UpdateWorld()
   -- render workd into a buffer and then copy buffer texture to a cubemap buffer
   for i = 1,6 do
       self.camera:SetRotation(self.cameraRotations[i])
       self.cameraBuffer:Enable()
       self.world:Render()
       self.cameraBuffer:Disable()
       self.cubebuffer:SetColorTexture(self.cameraBuffer:GetColorTexture(), 0, i-1) --write cambuffer to cubebuffer each face
   end
   Context:SetCurrent(self.context)

   material:SetTexture(self.cubebuffer:GetColorTexture())
   shader:Enable() -- enable skybox shader2
   self.cubebuffer:GetColorTexture():Bind(0) --assign cubemap texture from buffer into texture0
end

[Rastar]

Hi shadmar, thanks for the suggestion - will try over the weekend!

[shadmar]

If you just want to make an in-scene static cubemap you can do it like this :

http://www.leadwerks.com/werkspace/topic/11224-skybox-rendering/#entry82736